Sequential hermaphroditism is a fairly rare thing ... unless you're a reef fish. From clownfish and damselfish to angelfish and wrasses, a new study explores the dynamics and implications of fish that can change sexes.

Polls tracking pet ownership show that the number of fishkeepers (particularly marine fishkeepers) have increased in the USA over the past five years. However, over the same time period, UK fishkeepers have declined substantially. How is the fishkeeping scene where you live?

Have you ever wondered how brittle stars hide from light without eyes? Scientists have now discovered the mechanism for their eyeless "vision": The skin on the arms and bodies of brittle stars are covered with thousands of photoreceptors.

Marine aquarists have all experienced it: Reef fishes that naturally school simply refuse to in captivity? Common theories are that the lack of predators or the relatively small size of aquariums discourage schooling. A new study finds that noise plays a big role. Noisy water = less cohesive schooli...

Heteropsammia sp., otherwise known as "walking corals," can scoot around on the substrate thanks to spaghetti worms that live inside the coral's base. Now a new species of hermit crab has been also found to share this special relationship.

Many tetras are difficult to sex. Often, differentiation comes down to fin lengths, subtle color deviations, or sometimes just the "fullness" of their bellies. But with Hyphessobrycon myrmex, the color between the sexes is unmistakable, and that's a good thing because this species is tiny.

There hasn't been a whole lot of aquarium-relevant scientific papers published this month (or this year for that matter). Fortunately there are still a lot of really wonderful aquariums. This is Reefspy's 180g mixed reef. "True" mixed reef tanks are a rare breed these days, so we love it when we see...